The present disclosure relates to perforated geocells that have reduced tendency to deform when loaded during service. Also described herein are various systems using such geocells.
A geocell (also known as a cellular confinement system (CCS)) is a three-dimensional geosynthetic product originally designed by the United States Army Corps of Engineers (ACE) for fast deployment of troops on sandy dunes which generally could not support the load of heavy vehicles (e.g. trucks, tanks, etc). A geocell is an array of containment cells resembling a “honeycomb” structure that can be filled with infill, which can be cohesionless soil, sand, gravel, ballast, or any other type of aggregate. Confinement is provided in all directions, and internal force vectors act within each cell against all the walls. Geocells are used in civil engineering applications to prevent erosion or provide lateral support, such as retaining walls for soil; alternatives for sandbag walls or gravity walls; for roadway, pavement, and railway foundations; and for channel lining. Geocells also provide efficient reinforcement for relatively fine infills, such as sand, loam, and quarry waste.
Geocells are usually perforated, with apertures drilled or punched in the cell walls. The perforations provide improved friction with the infill, and also help with drainage. For example, U.S. Pat. Nos. 6,296,924 and 6,395,372 illustrate the use of perforations which are applied in two or four distinct “blocks” or groups, and which are separated by non-perforated “belts” which allegedly help maintain sufficient wall stiffness, as well as separate the perforations from the areas where welding will occur. FIG. 1 is a copy of FIG. 2 of U.S. Pat. No. 6,395,372. Here, four groups of perforations are seen, separated by belts in the areas labeled D3 and D6. This unbalanced distribution of perforations causes weakening of the perforated areas compared to the non-perforated belts, and result in an overall weakening of the cell wall. This can cause premature failure of the geocell at loads much lower than designed.
It would be desirable to provide perforated geocells that have improved stress and strain distribution over the entire cell wall, improved response to loads due to an even strain over the compete strip, improved strength due to the avoidance of weakened “blocks”, and that avoid uneven distribution of stresses.